A new mathematical framework is presented for producing maps and large-scale averages of temperature changes from weather station data for the purposes of climate analysis. This allows one to include short and discontinuous temperature records, so that nearly all temperature data can be used. The framework contains a weighting process that assesses the quality and consistency of a spatial network of temperature stations as an integral part of the averaging process. This permits data with varying levels of quality to be used without compromising the accuracy of the resulting reconstructions. Lastly, the process presented here is extensible to spatial networks of arbitrary density (or locally varying density) while maintaining the expected spatial relationships. In this paper, this framework is applied to the Global Historical Climatology Network land temperature dataset to present a new global land temperature reconstruction from 1800 to present with error uncertainties that include many key effects. In so doing, we find that the global land mean temperature has increased by 0.911 ± 0.042 C since the 1950s (95% confidence for statistical and spatial uncertainties). This change is consistent with global land-surface warming results previously reported, but with reduced uncertainty. 3 IntroductionWhile there are many indicators of climate change, the long-term evolution of global surface temperatures is perhaps the metric that is both the easiest to understand and most closely linked to the quantitative predictions of climate models. It is also backed by the largest collection of raw data. According to the summary provided by the Intergovernmental Panel on Climate Change (IPCC), the mean global surface temperature (both land and oceans) has increased 0.64 ± 0.13 C from 1956 to 2005 at 95% confidence (Trenberth et al. 2007).During the latter half of the twentieth century weather monitoring instruments of good quality were widely deployed, yet the quoted uncertainty on global temperature change during this time period is still ± 20%. Reducing this uncertainty is a major goal of this paper. Longer records may provide more precise indicators of change; however, according to the IPCC, temperature increases prior to 1950 were caused by a combination of anthropogenic factors and natural factors (e.g. changes in solar activity), and it is only since about 1950 that man-made emissions have come to dominate over natural factors. Hence constraining the post-1950 period is of particular importance in understanding the impact of greenhouse gases.The Berkeley Earth Surface Temperature project was created to help refine our estimates of the rate of recent global warming. This is being approached through several parallel efforts to A) increase the size of the data set used to study global climate change, B) bring additional statistical techniques to bear on the problem that will help reduce the uncertainty in the resulting averages, and C) produce new analysis of systematic effects, including data selection bias, urban hea...

Antimatter was first predicted in 1931, by Dirac. Work with high-energy antiparticles is now commonplace, and anti-electrons are used regularly in the medical technique of positron emission tomography scanning. Antihydrogen, the bound state of an antiproton and a positron, has been produced at low energies at CERN (the European Organization for Nuclear Research) since 2002. Antihydrogen is of interest for use in a precision test of nature's fundamental symmetries. The charge conjugation/parity/time reversal (CPT) theorem, a crucial part of the foundation of the standard model of elementary particles and interactions, demands that hydrogen and antihydrogen have the same spectrum. Given the current experimental precision of measurements on the hydrogen atom (about two parts in 10(14) for the frequency of the 1s-to-2s transition), subjecting antihydrogen to rigorous spectroscopic examination would constitute a compelling, model-independent test of CPT. Antihydrogen could also be used to study the gravitational behaviour of antimatter. However, so far experiments have produced antihydrogen that is not confined, precluding detailed study of its structure. Here we demonstrate trapping of antihydrogen atoms. From the interaction of about 10(7) antiprotons and 7 × 10(8) positrons, we observed 38 annihilation events consistent with the controlled release of trapped antihydrogen from our magnetic trap; the measured background is 1.4 ± 1.4 events. This result opens the door to precision measurements on anti-atoms, which can soon be subjected to the same techniques as developed for hydrogen.

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The status of the research on muon colliders is discussed and plans are outlined for future theoretical and experimental studies. Besides work on the parameters of a 3-4 and 0.5 TeV center-of-mass (COM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (COM) that could be a factory for the s-channel production of Higgs particles. We discuss the research on the various components in such muon colliders, starting from the proton accelerator needed to generate pions from 1098-4402͞99͞2(8)͞081001(73)$15.00 © 1999 The American Physical Society 081001-1 PRST-AB 2 CHARLES M. ANKENBRANDT et al. 081001 (1999) a heavy-Z target and proceeding through the phase rotation and decay (p ! m n m ) channel, muon cooling, acceleration, storage in a collider ring, and the collider detector. We also present theoretical and experimental R&D plans for the next several years that should lead to a better understanding of the design and feasibility issues for all of the components. This report is an update of the progress on the research and development since the feasibility study of muon colliders presented at the Snowmass '96